Tobacco smoke filters



United States Patent 3,426,765 TOBACCO SMOKE FILTERS James R. Misenheimer and Charles H. Keith, Charlotte,

N.C., assignors to Celanese Corporation, New York,

N .Y., a corporation of Delaware No Drawing. Filed Feb. 21, 1967, Ser. No. 617,500 U.S. Cl. 131267- 12 Claims Int. Cl. A24b 15/02 ABSTRACT OF THE DISCLOSURE A tobacco smoke filter capable of removing numerous undesirable components from a tobacco smoke stream comprising a carrier material and a minor amount of certain di-substit-uted amides.

A large number of materials have been proposed as filters for tobacco smoke. Cellulosics and in particular cellulose acetate are the most commonly employed carrier materials. Although these materials remove a certain proportion of the particulate, or liquid-solid phase of tobacco smoke, these materials are of little value in removing the constituents in the gaseous phase of the smoke. It is known that although some of the gaseous constituents of tobacco smoke are desirable from the standpoint of taste, flavor and aroma, others are undesirable and are quite irritating to the smokers throat and lungs.

The art discloses that the addition of certain powdered additives to the carrier material effects the selective removal of undesirable components from the smoke stream. Powders, however, present many problems such as processing difliculties and the deposition of particles in the smokers mouth. Moreover, solid adsorbents such as charcoal remove many of the tasteand aroma-imparting components. Certain plasticizing liquid additives are known which can be easily applied and can selectively remove specific components. However these prior art liquid additives tend to selectively remove only a few of the various undesirable components, and furthermore the extent of removal of these components is often low.

It is an object of this invention to provide a liquid additive-containing tobacco smoke filter which can selectively remove many of the undesirable components of the vapor phase of tobacco smoke. It is a further object that this filter exhibit a high degree of removal of the individual undesirable components. As a still further object, the liquid additives should additionally serve as bonding agents to increase the firmness of the filter.

We have now. discovered that these objects can be realized by tobacco smoke filters containing certain aliphatic di-substit-uted amides. These di-substituted amides which afford such high selectivity have the formula:

wherein R is an aliphatic hydrocarbon radical having 4 to 12 carbon atoms and R and R are lower alkyl radicals. The preferred R groups are alkyl. The preferred compound of this class is N,N-dimethylcaprylamide. Other representative compounds are N,N-diethyl caproamide and N,N-methylethyl heptylamide.

These di-substituted amides can be formed in known manner as for example, the reaction of the corresponding secondary amine with a suitable carboxylic acid derivative. The acid halide is the preferred carboxylic acid derivative for this purpose.

3,426,765 Patented Feb. 11, 1969 These amides are bonding agents. They can be incorporated into tobacco smoke filters by various means well known in the art. The amount added should be such as to be present in the filter in an amount of from 10* to 50 by weight based on the weight of carrier material. Preferably this amount should be about 20 to 35%.

The relative filtration abilities of filter elements can be demonstrated in a simple manner by the following chromatographic procedure. Test filters of 50 mm. each are prepared from cellulose acetate cigarette tow and sprayed with the liquid additive by means of a centrifugal plasticizer applicator on the filter rod-making machine in the conventional manner. The standard cellulose acetate tow employed in the examples below was uniformly crimped and had a regular cross section, a total denier of 55,000 and a denier per filament value of 3.9.

These test filters are then attached to selected mm. commercial cigarettes tobacco columns of equal weight and smoked on a six-port smoking machine. In this smoking system, six cigarettes are puffed upon to provide a common vapor sample. A 35 ml. puff of two seconds duration is utilized and the cigarettes are lit at one minute intervals.

A five milliliter aliquot of the sample consisting of a mixture of the second through seventh puffs is prepared and injected into a chromatographic column through the sampling valve. The chromatographic column employed in the examples below comprised 2 foot and 15 foot sections of inch stainless steel tubing in series, the first containing diisodecyl phthalate on Chromosorb W, and the second 18% 3,5-oxydipropionitrile and 2% di(2- methoxyethyl) phthalate on Chromosorb' W. Nitrogen flowing at a rate of 30 ml./min. is used as a carrier gas. The program consists of 5 minutes at 25 C., 15 minutes increasing to and holding at 55 C., 1 minute increasing to 67 C., 9 minutes holding at 67 C., 1 minute increasing to 87 C., and holding at this temperature for the remainder of the run. This chromatographic system gives reasonably rapid} analysis with suitable resolution of components, and yields some 23 peaks within approximately 35 minutes.

Vapor yields are measured in terms of these peak heights for significant components of the mixture. These vapor yields in turn are used to compute vapor retention efficiencies (V.R.E.) of the test filters (F as compared to equivalently prepared and smoked untreated filter cigarettes (F according to the formula:

vapor The theoretical maximum for a test filter that removes all of the subject component is of course The data in Table I below relates to an overall rating of vapor retention for ten significant components of the mixture by averaging their individual vapor retention efliciencies. The ten components, representative of the various functional organic groups, were isoprene, acetaldehyde and furan, Z-methylfuran and propionaldehyde, methanol, acrolein, benzene, acetone, Z-butanone, toluene and 2,3-butanedione.

The removal efiiciency of these above-mentioned 10 significant components are listed for filter cigarettes prepared and tested by the above procedure, and containing (1) no liquid additive, or (2) the commonly employed plasticizer glyceryl triacetate (triace'tin ot (3) an illustrative additive of this invention, N dimethyl caprylamide. Both additives were employed --1n an amount of 26% by weight based on the weight of cellulose acetate.

The data in Table II relates to the individual vapor removal etficiency as above described of five selected components which are representative of major irritants in tobacco smoke. Filters of the type described above and employed in Table I are also used herein.

TABLE II.VAPOR REMOVAL EFFICIENCY (PERCENT) Liquid additive Isoprene dAeetal- Methanol Acetone Toluene ehyde None 0 0 0 0 Glyceryl triacetate 0 4 32 23 23 N,N-dimethyl caprylamide 14 23 81 45 92 It is thus apparent from Tables I and II that the disubstituted amide liquids additives of this invention confer high selective removal properties on tobacco smoke filters.

Although the efficiency of the di-substituted amide additives of this invention have been demonstrated only in connection with cellulose acetate, other carrier materials can be employed since the vapor removal efiiciency is not critically dependent thereon. The term carrier materials" used herein includes such materials as wood pulp, cotton, paper, cellulose esters in flake or fiber form, regenerated cellulose, fibrous polyolefins, silica gel, alumina, tobacco and the like.

Other additives can be incorporated into the tobacco smoke filters of this invention in known manner, as, for example, the inclusion of menthol to impart a desired taste.

What is claimed is:

1. A tobacco smoke filter adapted to remove numerous undesirable components from a tobacco smoke stream comprising a carrier material and from to 50% by weight based on the weight of said carrier of a compound having the formula:

wherein R is an aliphatic hydrocarbon radical having 4 to 12 carbon atoms and R and R" are lower alkyl radicals.

2. A tobacco smoke filter according to claim 1 wherein said carrier material is a cellulosic.

3. A tobacco smoke filter according to claim 1 wherein said carrier material is cellulose acetate.

4. A tobacco smoke filter according to claim 3 wherein the amount of said compound is about 20 to 35% by weight based on the weight of cellulose acetate.

5. A tobacco smoke filter according to claim 1 wherein R is an alkyl radical.

6. A tobacco smoke filter according to claim 5 wherein R and R" are methyl.

7. A tobacco smoke filter according to claim 1 wherein said compound is N,N-dimethylcaprylamine.

8. A tobacco smoke filter according to claim 4 wherein said compound is N,N-dimethylcaprylamide.

9. A tobacco smoke filter element adapted to remove undesirable components from tobacco smoke which comprises a carrier material and as an additive thereto an amine salt, said salt being derived from a secondary alkyl amine having lower alkyl radicals and an aliphatic carboxylic acid having 4 to 12 carbon atoms.

10. A tobacco smoke filter adapted to remove numerous undesirable components from a tobacco smoke stream, comprising a carrier material having thereon a compound of the formula:

0 R Rink-R" wherein R is an aliphatic hydrocarbon radical having 4 to 12 carbon atoms and R and R are lower alkyl radicals.

11. A tobacco smoke filter according to claim 10 wherein said compound is N,N-diethyl caproamide.

12. A tobacco smoke filter according to claim 10 wherein said compound is N,N-methylethyl heptylamide.

References Cited UNITED STATES PATENTS 2,920,416 1/1960 Kinnavy l3l266 X 2,968,306 1/ 196 1 Touey et al 131-266 3,127,901 4/1964 Whitefield et a1 131-267 3,246,655 4/1966 Spears et a1 13l-266 X SAMUEL KOREN, Primary Examiner.

DENNIS I. DONOHUE, Assistant Examiner. 

